Anna Walentynowicz who died, aged 80, in the Smolensk plane disaster was the woman who began one of Poland's most significant postwar events – the Gdansk shipyard strike in 1980 that led to the formation of the Solidarity trade union and, ultimately, the collapse of communism.

A Polish free trade unionist it was her sacking in August 1980 that provoked the strike at the Lenin shipyard in which more than a million workers would eventually be involved. She went on to play herself in film-maker Andrzej Wajda's seminal depiction of the strike and the era in which it took place, Man of Iron.

A welder and then a crane operator at the yard, in her youth Walentynowicz was a member of Poland's Communist party. Appalled, however, by the corruption that she encountered and the suppression of free speech, she became involved in producing and distributing Robotnik Wybrzeza (Coastal Worker), a newspaper which she handed out in the shipyard, even to her Communist bosses.

The trigger for her disaffection with the party was said to be her discovery that one of her bosses had stolen money from her fellow employees and used it to participate in a lottery.

It was not only corruption that incensed her but the gradual realisation that far from helping to make Poland a better place for the people, workers' rights and freedom of speech were being trampled on.

Despised by the shipyard's management, later in her working life she would be segregated from other employees for her actions. The crisis would come, however, when the management finally moved against her in August 1980, firing her a few months before she was due to retire.

It was this clumsy action that led to the strike, which occurred in the midst of a period of profound political and economic problems for the Communist regime. The consequence of that action, led by then electrician Lech Walesa, was the emergence of Solidarity and also the Gdansk Agreement, which saw the government give in to the workers' demands for a new social contract. Within two years the union would have 10 million members.

Later, however, Walentynowicz would fall out with Walesa, leaving Solidarity and criticising Walesa's leadership. After the fall of communism in 1989 she distanced herself still further from the union.

Speaking yesterday, however, Walesa said: "This is a great tragedy, a great shock to us all."

• This article was amended on 12 April 2010 to correct one reference to the date of Anna Walentynowicz's sacking.